Arizona's execution is the third botched or problematic execution this year. And it poses lots of legal questions. So we have NPR legal affairs correspondent Nina Totenberg now to answer them. Hi.

NINA TOTENBERG, BYLINE: Hi.

SIEGEL: First, can you describe what happened last night in terms of last-minute appeals including the U.S. Supreme Court?

TOTENBERG: Well Wood's lawyers actually left the execution viewing room after about an hour and filed motions with the state Supreme Court and the U.S. Supreme Court to stop the execution. The state court was 10 minutes into a telephone hearing when Wood died. Here in Washington, the Supreme Court received the lawyer's request to halt the execution at 6:27 p.m. Eastern time. And that motion was immediately referred to Justice Kenned, who is the justice assigned to that part of the country. 19 minutes later, he refused to halt the execution. And three minutes after that, Wood died.

SIEGEL: How does the court actually handle these matters? Does it have a system for doing this?

TOTENBERG: Oh, yes. There's someone at the court known informally as the death clerk. And his or her job is to keep everyone in the loop. They make up a list every week of all the pending executions throughout the country. They stay in touch with the lower courts and with counsel. And that's their job. And to make sure that the justices get all the papers in these cases.

SIEGEL: But what if a justice isn't there.

TOTENBERG: Well, it really doesn't matter. There's a clerk there in each of the chambers. In fact, once I was at the theater, and I went in intermission to make a call on a pay phone in those days. And Justice O'Connor was at the payphone next to me calling in to check on the progress of a death case where, I assumed, there was an execution scheduled for the evening.

SIEGEL: Let's take a hypothetical - what would've happened if the execution in Arizona yesterday had, in fact, been halted? Could the inmate had been revived?

TOTENBERG: They tell me yes, that there are in fact protocols for the executions that include procedures to bring the inmate back to life if something goes wrong.

SIEGEL: So the next question then would be if he had been revived, would it be cruel and unusual punishment to try and execute him again later?

TOTENBERG: Well, you know, this isn't entirely a hypothetical. In 2009, in Ohio, the governor called off an execution after prison officials tried unsuccessfully for two and a half hours to find a vein to inject the lethal drugs. After that failed attempt, the state sought to reschedule the execution. And now the Ohio Supreme Court is considering whether that would violate the Constitution's ban on cruel and unusual punishment. And the U.S. Supreme Court actually ruled on this issue more than six decades ago, in 1946, when the state of Louisiana tried to execute a black 17-year-old convicted by an all-white jury of murder. And because the electric chair had been improperly hooked up, the chair shook but the electric jolts didn't work. And the kid started screaming, I'm not dying. So when the state tried to execute him again, the case went to the Supreme Court. And the court by a 5-4 vote ruled that an equipment failure didn't constitute cruel and unusual punishment. But the fifth justice, Justice Felix Frankfurter, was so anguished by his vote that he secretly sent a friend to try to persuade the governor to grant clemency in the case. Of course, it failed.

SIEGEL: Well, getting back to these more current botched executions. Why are we seeing this more and more when, as I understand it, the Supreme Court in 2008 upheld the use of a three-drug cocktail as acceptable when properly administered?

TOTENBERG: Look, there is an inherent tension here. The more pressure there is to do this the right way from anti-death penalty lawyers, the more secretive the states get because they can't actually carry out their mandate in the most humane way anymore. In fact, there's been no independent investigation of any of these problematic executions. All of these investigations have been conducted by the Departments of Corrections in the states involved, not by some independent group of people.